A lichen pollution test

Plants called lichens are sensitive to air pollution, especially the air’s acidity, so you can use their presence or absence to see how clean your air is. Shrubby and leafy lichens only survive in clean air. In the most polluted areas there are none at all. Look for lichens on walls, stones and trees, and use this scale to rate the air quality.

Pollution

Pollution is now a major problem in marine ecosystems. Over 80% of this comes from land-based activities, e.g. sewage and industrial waste. Conditions are worst in enclosed areas like the Mediterranean and the North Sea, where levels of pollution are now so high that wildlife and human health are threatened.

Drum containing – dangerous radioactive nuclear waste dumped at sea. Measures are finally being taken to combat this international problem, but it will be a long and difficult job.

Transport and pollution

Pollution from the ever-growing volume of vehicle exhaust is making life more and more unpleasant in many of the world’s major cities. Ozone, carbon monoxide, hydrocarbons and lead and dust particles all endanger the health of the cities’ people and wildlife.

The removal of lead from petrol and the use of devices known as three-way catalytic converters to control exhaust fumes are two ways of lessening the problem.

In Tokyo, Japan, special electronic signs show the levels of noise and air pollution.

Soil erosion

Most of the earth’s surface is covered by a layer of soil, ranging from 0,5 cm thick in mountainous regions to 2 m in cultivated areas. We all depend on this thin layer for our food supplies, yet everywhere it is threatened by soil erosion.

Over-grazing, poor irrigation, intensive farming and the destruction of tree cover mean that vital topsoil is left exposed, and much is being blown or washed away. If this continuous, we may not left to grow enough food.

2.9. Fill in the correct word derived from the word in bold.

One person, the American (1) …….. Thomas Midgely, created what are considered to be two	INVENT
of today’s biggest (2) …….. evils – CFCs and leaded petrol.	ENVIRONMENT
His inventions show how science can (3) …….. practical	COME
problems but how (4) …….. perfect ideas can	APPEAR
have (5) …….. consequences. After WW1, Midgely	DISASTER
was searching for a chemical (6) …….. to the problem of an irritating knocking sound heard coming from	SOLVE
car engines. This saw the (7) …….. of leaded petrol.	DEVELOP
Nowadays, most (8) …….. believe that lead causes	SCIENCE
(9) …….. pollution and brain damage in young children.	ATMOSPHERE
Midgely then turned to the refrigerator industry in an attempt to make (10) …….. to the cooling systems. He developed a substance known as CFC, which as we know, is damaging the earth’s ozone layer.	IMPROVE
In 1940, Midgely was paralysed by polio. He invented a pulley system to (11) …….. him to get out of bed. Sadly, in 1944 he strangled himself while using it.	ABLE

2.10. Fill in the correct word derived from the word in bold.